function popdiv(popdiv, width, height, alpha) {

    var A = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop || 0;
    var D = 0;
    D = Math.min(document.body.clientHeight, document.documentElement.clientHeight);
    if (D == 0) {
        D = Math.max(document.body.clientHeight, document.documentElement.clientHeight)
    }
    var topheight = (A + (D - 300) / 2) - 50 + "px";
    //$("#popbg").css({height:$(document).height(),filter:"alpha(opacity="+alpha+")",opacity:alpha})
    //$("#popbg").fadeIn();
    $(popdiv).removeClass();
    $(popdiv).attr("class", "pop_out ");
    $(popdiv).css({left: (($(document).width()) / 2 - (parseInt(width) / 2)) + "px", top: topheight});
    $(popdiv).fadeIn();
}